Ipomoea batatas is a member of the morning glory family Convolvulaceae. The cultivated members of Ipomoea batatas are commonly produced for consumption of their enlarged storage roots and they are commonly referred to as the white or yellow sweetpotato and the orange yam. The plants of the edible sweetpotato types are typically fast-growing, green vines possessing a wide variety of leaf shapes ranging from palmate and deeply lobed, to cordate or triangular shaped leaves with no lobes. Ornamental sweetpotatoes, which have been bred and selected for their unique foliage colors, leaf shapes, and plant habits, typically do not produce large fleshy storage roots like the sweetpotato cultivated for consumption. The storage roots produced by ornamental sweetpotatoes are typically not as large because no selection has been exercised for yield, thus storage roots do not begin to swell until very late in the season and those that are produced are not very attractive.
Like their cultivated forms, ornamental sweetpotato plants are a heat loving, drought tolerant vines grown as an annual, but they possess unique foliage colors, leaf shapes, and growth habits, which have significant value in the ornamental marketplace. They are highly desirable in the landscape and ornamental industries because their foliage comes in a wide variety of colors and shapes. Also, they can be grown in a potted plant and/or mixed planting format, and they have the ability to cover a large space or hang over walls and pots creating brightly colored and textured backdrops in gardens and patios. Most ornamental sweetpotatoes grow and last the entire growing season and they require little maintenance. Moreover, these plants have few insect or disease problems.
Until the release of the Sweet Caroline series of ornamental sweetpotatoes (see below) there were six popular types of ornamental sweetpotatoes, cultivated primarily as annual, summer vines in landscaping applications. These six cultivars are: ‘Blackie’ (unpatented), having purple foliage and lavender flowers; ‘Terrace Lime’ (unpatented) and ‘Margarita’ (unpatented; also known as ‘Sulfur’), which have large brilliant chartreuse leaves and lavender blooms; ‘Black Heart’ (unpatented; also known as ‘Ace of Spades’), having heart-shaped leaves with burgundy purple color; ‘Tricolor’ (unpatented; also known as ‘Pink Frost’), a variegated plant having pale green, white, and pink-margined leaves; and ‘Lady Fingers’ (unpatented), which has medium green, dainty leaves divided into long, thin, finger-like lobes which are complemented by burgundy stems and veins.
To meet the growing horticultural demand for ornamental sweetpotatoes it is desirable to produce new cultivars of ornamental sweetpotato with attractive foliage colors, leaf shapes, and plant architectures. In addition, it would be advantageous to develop cultivars of ornamental sweetpotato exhibiting a more compact growth, and which do not out-compete other species in mixed containers.
‘NCORNSP-012EMLC’ was bred to meet the increasing demand for new ornamental sweetpotatoes. ‘NCORNSP-012EMLC’ is a compact, semi-upright; mounding, spreading variety producing many short shoots. This variety is distinguishable from other varieties by its very deeply-lobed light green to chartreuse colored leaves and its compact, highly branched plant habit. The plant has good vigor and distinctive twisting and outwardly curved petioles, causing leaves to be presented on a horizontal plane. The production of flowers by ‘NCORNSP-012EMLC’ is rare even under short day conditions. In greenhouse and field trials conducted since 2005 by the breeding program and industry collaborators ‘NCORNSP-012EMLC’ has been shown to be much less vigorous than Ipomoea batatas ‘Margarita’ and ‘Blackie’ and is suitable for use as a landscape or containerized plant.
‘NCORNSP-012EMLC’ originated from a conventional cross between the proprietary Ipomoea batatas cultivar ‘NC2591-002ORN’ (the female parent; unpatented) and the proprietary Ipomoea batatas cultivar ‘NC2279-001ORN’ (the male parent; unpatented) conducted during October 2004 to April 2005 in a greenhouse in North Carolina. Botanical seed of the ‘NC2591-002ORN’×‘NC2279-001ORN’ cross were planted in the greenhouses in North Carolina in Spring 2005. The first cycle of selection on this family was exercised in the seedling trays and survivors were transferred to a single 6-inch pot, which was then maintained in the greenhouse. Cuttings (2 each) were taken from the plants in April and planted at greenhouses in North Carolina as 2-plant un-replicated plots during late June to early July 2005. The single, individual clone now known as ‘NCORNSP-012EMLC’ was selected on Sep. 1, 2005 because of its combination of exceptional ornamental sweetpotato features, and has been propagated asexually since that time.
Since its selection, ‘NCORNSP-012EMLC’ has been asexually reproduced in greenhouses in North Carolina predominantly by vegetative propagation of vine cuttings. Successively, there have been five cycles of vegetative propagation, one cycle of tissue culture micro propagation and multiple vegetative propagation cycles to increase the plant population. Asexual reproduction of ‘NCORNSP-012EMLC’ by vine cuttings has shown that the unique features of the new cultivar are stable and the plant reproduces true to type in successive generations of asexual reproduction.